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RAV4 kills "new" battery in about 4 days

I own a 2004 RAV4 with 150,000 miles. I bought it used in Jan 2011. Anytime I left it sitting for more than 8 days it would draw the battery down to dead. I took it to my mechanic, who at that time could not find a draw, so we got a new battery. I went with top of the line Interstate Battery. I was not convinced that was the problem, and I was right. Now it kills the battery in 4 days. AND with it having gone dead 3-6 times in the past 6 months, the new battery is now at best 75% of power (according the the quick tester I have–which works because 6 months ago it said the battery was 100%). I took it back and my mechanic (who btw never charges me when he can’t find a problem!) He ran all the tests again and again did not find any draws. He said he watched all the computers go to sleep like they should, and only found something like 1miliamp of draw … BUT obviously something is killing the battery. Could something be coming back on after a few hours. Additonal info: It has a dealer installed alarm system that truly does not seem to work properly, or I just don’t know how to use it. AND it has an after market JVC radio. I was thinking it was one of these, but again, the mechanic said neither shows a draw … I’m stumped and frustrated. I am not prepared to spend hundred of dollars at a dealer, but I’m feeling like Ihave to take it to a second opinion mehanic. I live near Asheville NC. How can I try and figure this out myself Is there a simple tool I could attach to the battery to see draw amperage–I could test it every few hours when it’s sitting and see if it spikes … OR any other ideas

This kind of trouble can be hard to find since it appears the trouble is intermittent. I know there are special testers made that can monitor current draw and even have a preset-able alarm point. That would be nice to have for this but may cost more money than you would want to spend on this. There are some digital meters on the market, like from Fluke, that will record min/max readings seen by the meter and they aren’t real expensive (say under 150 dollars). Check out the Fluke Model 114. It can store the max current for a period of time so you can check it over time. It won’t sound an alarm if a problem happens. If you do see a problem you could try monitoring suspected trouble circuits at the fuse connection points and see if the trouble is on that circuit.

Call your mechanic and ask him what method he used to locate the current draw. This could make all the difference.

Tester

When I hear of a vehicle that kills a battery every couple of days, my first question is “What else is not working?” You have already answered that question.

Jacqui,
The ONLY way to discover what is causing this problem is eliminate sources of the draw by pulling fuses, one at a time until the parasitical draw stops.
Start with a baseline (control) reading of the battery using your quick tester at 4 or 8 or 12 hours after the engine is shut off. Then after normal running of the vehicle and parking it for the day, after you turn off the vehicle, pull a fuse, wait the same amount of time as when you took the baseline reading, and take a test (experimental) reading. You will know when the right fuse has been pulled. If possible, identify what circuit is served and proceed with troubleshooting and repair.
There are several fuse boxes. One in the cabin and several in the engine compartment. Consult the user manual (or your mechanic). Make a sketch (schematic) of the fuse boxes and keep track of which fuses have been pulled. Make a log of the battery tester readings after each circuit is tested.
Before starting the vehicle again, replace the fuse, and log the reading.
The only inconveniences will be having to re-set the clock and the radio settings when that fuse is pulled…
Also, when the fuse to the ECU (computer) is pulled, it might re-set the pollution control memory. It can take up to 100 miles and driving for ten-15 minutes above 55 miles per hour to re-set the readings. This is only significant if you have a near-term appointment for an EPA reading.

There could be other problems, such as a bad alternator, bad battery post connections, bad battery cables (conductor or insulation), stuck(“leaky”) starter solenoid or battery to starter cable.
Good luck and let the rest of us know what you find.